PROBLEM TO BE SOLVED: To provide a tool holder capable of performing motion close to lathe turning, and to provide a machine tool provided with the tool holder.SOLUTION: A tool 2 is mounted on a turntable 12 via a first beam 14 having some rigidity. The first beam has its one end secured to the turntable 12 so that its axis overlaps a rotation center axis 4, and to the other end of the first beam, the tool is secured. A first weight 6 is secured to the other end side portion of the first beam. In the stationary state of the turntable, the first weight 6 is secured to the first beam in a position not superimposed on the rotation center axis 4 and, thereby, when the turntable is rotated, by centrifugal force Fc acting on the first weight, the other end of the first beam on the side where the tool is secured is shifted outward from the tool rotation center axis. Thereby, the tool is rotated around the tool center axis with a tool rotation radius Rt and the tool rotation radius Rt changes in accordance with the rotation speed of the turntable.